feature section: virtualization in the mainstream · 2007-07-27 · puneet DhAwAn sIMon CRosBy...
Transcript of feature section: virtualization in the mainstream · 2007-07-27 · puneet DhAwAn sIMon CRosBy...
feature section: virtualization in the mainstream
DELL POWER SOLUTIONS | August 200734 Reprinted from Dell Power Solutions, August 2007. Copyright © 2007 Dell Inc. All rights reserved.
V irtualization can offer multiple advantages in enter-
prise environments, including increased resource uti-
lization, efficient server consolidation, scalable test
and development environments, and high availability through
dynamic provisioning. The Xen hypervisor at the core of the
XenSource XenServer software family can provide these same
benefits along with additional features, including a powerful
virtualization architecture called paravirtualization. Combining
XenSource software with standards-based Dell PowerEdge serv-
ers and the Dell OpenManage systems management suite can
provide an excellent platform for virtualized data centers.
comparing emulation virtualization and paravirtualization First-generation emulation hypervisors present each virtual
machine (VM) with an emulated hardware layer that offers
the guest OS the illusion of a standard server with standard
hardware devices. When a running guest OS attempts to
control the hardware using privileged instructions, the
hypervisor stops execution and emulates the legacy hard-
ware device, hiding the real hardware. It then patches the
OS code of the running guest in real time to help ensure that
its future hardware access functions correctly. Of course,
this complexity can reduce performance, much as emulated
floating-point computation did prior to the implementation
of hardware floating-point support.
Paravirtualization, pioneered by the XenSource founders,
can deliver near-native performance for VMs while helping
ensure that physical resources are shared between them in
a balanced way. Xen guest operating systems interface with
the hypervisor through the hypercall application program-
ming interface (API) rather than through hardware emula-
tion. This approach allows the hypervisor and OS to
cooperate to optimally virtualize the underlying hardware
and schedule guest OS virtual processors and I/O, helping
increase performance, security, and portability compared
with emulation virtualization.
Another key advantage of Xen paravirtualization is that
it can reuse the hardware qualification and driver certifica-
tion of existing operating systems. The driver stack is simply
a standard OS, certified on the hardware by the system
vendor, with specific privileges to perform I/O to real hard-
ware on behalf of other guest operating systems. This use of
an off-the-shelf OS helps eliminate the need to import drivers
into a separate hypervisor.
Both Intel® Virtualization Technology and AMD
Virtualization™ technology provide a processor-level hardware-
accelerated vector that automatically enters the hypervisor
(akin to a hardware hypercall) when a running guest OS
executes a privileged operation. Intel and AMD also offer
instructions allowing Xen guests to benefit from paravirtual-
ized I/O. Many servers—including ninth-generation Dell
Related Categories:
Dell PowerEdge servers
Dell PowerVault storage
Virtualization
Xen virtualization
Visit www.dell.com/powersolutions
for the complete category index.
Using XenSource XenEnterprise with Dell Servers and Dell OpenManage
Combining XenSource XenEnterprise software with Dell™ PowerEdge™ servers can provide a scalable, efficient virtualized environment in enterprise data centers. This article describes key features of XenEnterprise 3.2 and outlines how administrators can install and configure Dell OpenManage™ software to simplify management of XenEnterprise hosts.
By VICtoR MAshAyekhI, ph.D.
puneet DhAwAn
sIMon CRosBy
RogeR B. A. kloRese
paravirtualization can deliver near-native per-formance for VMs while helping ensure that physical resources are shared between them in a balanced way.”
35www.dell.com/powersolutionsReprinted from Dell Power Solutions, August 2007. Copyright © 2007 Dell Inc. All rights reserved.
PowerEdge servers—now support this hardware assistance for virtualiza-
tion, likely signaling the end of first-generation emulation. Figure 1 illus-
trates some of the key differences between these two approaches.
Exploring XenSource XenEnterprise The XenSource XenServer 3.2 family—comprising XenEnterprise,
XenServer, and XenExpress software—is designed to offer the advan-
tages of Xen paravirtualization as part of a comprehensive, easy-to-
use enterprise virtualization solution. XenEnterprise, built on the open
source Xen hypervisor, enables multiple levels of consolidation for
mainstream servers and is designed to support both Microsoft®
Windows® and enterprise Linux® operating systems, including the
same set of server hardware, storage, and I/O devices as standard
enterprise Linux distributions. It incorporates the Xen hypervisor,
easy-to-use installers for Xen and guest operating systems, physical-
to-virtual (P2V) conversion tools to help administrators virtualize
existing server OS installations, and a multi-server management con-
sole in a single package.
XenServer and XenExpress include differ-
ent functionality subsets of XenEnterprise at a
lower cost: XenServer offers high-performance
virtualization for Windows-based VMs while
providing the same multi-server management
capabilities as XenEnterprise, and XenExpress
offers free entry-level server virtualization for
Windows- and Linux-based VMs with single-
server management. Administrators can easily
upgrade servers from XenServer or XenExpress
to XenEnterprise without reinstalling the soft-
ware or losing VM configurations, in many
cases simply by entering a new license key.
Xensource Xenenterprise architecture XenEnterprise is a virtualization platform for
Windows and Linux guest operating systems
that is designed to support both paravirtualized
and fully virtualized VMs and to deliver fast
paravirtualized I/O for all guest operating sys-
tems. It utilizes Intel Virtualization Technology
and AMD Virtualization—both of which are
available on ninth-generation Dell PowerEdge
servers—to run Windows and other unmodified
guest operating systems. In addition, Microsoft
Services Premier Support customers can utilize
Microsoft support for the Windows guest oper-
ating systems running on XenEnterprise.
Deploying XenEnterprise in enterprise data centers can help admin-
istrators enhance the performance of legacy Windows and Linux sys-
tems while still taking advantage of the paravirtualization support in
later Windows and Linux OS releases. In XenSource tests, for example,
the combination of paravirtualization and hardware-assisted virtualiza-
tion, coupled with the enhanced disk and network drivers for Windows
supplied in XenEnterprise, delivered performance comparable to that
of other leading virtualization platforms across a broad range of
Windows benchmarks. XenEnterprise also delivered significant perfor-
mance increases over traditional binary translation virtualization for
Linux benchmarks.1
Figure 2 illustrates the virtualization architecture of XenEnterprise 3.2.
XenEnterprise is based on the Xen hypervisor, which is loaded directly on
the server hardware when the server is booted. The hypervisor boots a
privileged VM known as Domain 0 (Dom0), which is based on the
Community Enterprise Operating System (CentOS) 4 distribution and pro-
vides management services for other VMs. Within Dom0, the back-end
Xen toolstack
Userapplications
Linuxguest OS
Userapplications
MicrosoftWindowsguest OS
ConsoleOS
Devicedriver
Microkernel
Hardware Hardware
Emulation virtualization Xen paravirtualization
Devicedriver
Virtualization stack
Devicedriver
Devicedriver
Devicedriver
Userapplications
Linuxguest OS
Userapplications
MicrosoftWindowsguest OS
Xen hypervisor
Xen hypercall API
• uses a mini-os under the guest os• Requires binary patching of the os at runtime and device emulation• stores device drivers within the hypervisor
• uses a small, efficient hypervisor well suited for hardware virtualization• enables the guest os to cooperate with the hypervisor for resource management and I/o• stores device drivers outside the hypervisor• Can provide significant performance gains for paravirtualized linux
Figure 1. Emulation virtualization compared with Xen paravirtualization
1 For a detailed performance analysis, see “A performance Comparison of Commercial hypervisors,” by Xensource, www.xensource.com/performancepaper200703.
Reprinted from Dell Power Solutions, August 2007. Copyright © 2007 Dell Inc. All rights reserved.
I/O drivers that provide access to devices per-
form I/O on behalf of the front-end drivers in
other VMs; these I/O operations are passed
through a high-performance memory-mapped
communications channel within the Xen hyper-
visor known as XenBus.
Dom0 also runs the agent infrastructure
used to provide and coordinate VM manage-
ment services and life cycle control; adminis-
trators can access Dom0 through a graphical
user interface (GUI) or command-line interface
(CLI). Interactions with the hypervisor are then
performed through the control API, for which
processes running in Dom0 serve as the client
for the server provided by the hypervisor. For
VMs using hardware-assisted virtualization
(primarily Windows guest operating systems,
but also Linux guest operating systems
that take advantage of installation processes
using in-place P2V technology), the open
source QEMU emulator provides basic I/O services for installation and
boot until the optimized paravirtualized drivers are loaded, as well as
support services for low-speed devices such as CD drives.
Xensource Xenenterprise features XenEnterprise is designed to enable administrators to consolidate
server deployment and management easily and cost-effectively, sup-
porting targeted workloads such as file, print, Web, directory, and
infrastructure services; multiple development and testing environ-
ments and multitiered applications; and branch office and depart-
mental consolidation. In addition to the efficient, high-performance
virtualization provided by the Xen hypervisor, XenEnterprise provides
the components of a comprehensive virtualization platform, including
the following features:
• A simplified bare-metal installer that helps administrators quickly
prepare Dell PowerEdge servers for Xen virtualization, either by
booting from a CD—or a virtual CD provided by the Dell Remote
Access Controller (DRAC) management interface—and answering a
few simple questions, or by preparing an answer file and installing
the software using Preboot Execution Environment (PXE) boot
• Optimized disk and network drivers for Windows guest operating sys-
tems, helping increase I/O performance for critical services
• A one-to-many administrator GUI available from Windows- and Linux-
based management stations that administrators can use to create,
manage, and monitor multiple VMs and interact with their consoles
or, alternatively, launch other desktop interfaces such as Windows
Remote Desktop (see Figure 3)
• A powerful CLI for managing the VM life cycle from creation through
start, stop, suspend, and resume iterations, helping manage VM con-
figuration, allocation, and associated storage
• The ability to clone VMs through the GUI or CLI and export them to a
desktop system or another server, preparing them for import to the
same or another XenEnterprise system
• Guest OS installers and P2V conversion tools for common Linux dis-
tributions, providing rapid Linux-based VM implementation and
deployment
XenSource also plans for XenEnterprise to soon provide an increased
range of data center–class features, including the following:
• A 64-bit hypervisor, offering support for both 64- and 32-bit guest
operating systems as well as increased physical and guest OS
memory
• Support for shared storage as well as enhanced Fibre Channel and
iSCSI integration
• Live and static migration of VMs between servers
• An XML-RPC API offering control over VM life cycles and server and
storage configuration as well as enhanced scripting and management
software integration
Using Dell OpenManage software with XenSource XenEnterprise hosts Ninth-generation Dell PowerEdge servers are designed to scale efficiently
and optimize virtualized workloads, supporting Intel Virtualization
Technology or AMD Virtualization, quad-core processors, large amounts
Figure 2. XenSource XenEnterprise architecture
Advanced I/Ofeatures such
as an intrusiondetection system
Dell PowerEdge server (Intel VirtualizationTechnology or AMD Virtualization)
Virtualization stack
Userapplications
Linuxguest OS
Userapplications
MicrosoftWindowsguest OS
Xen hypervisor
Xen hypercall API
Userapplications
Solarisguest OS
Dynamicmultipathing,copy-on-write,
volumemanagement
Networkvirtualization
Storagevirtualization
Xen
tool
sta
ck
Xen
man
agem
ent A
PIXen
controlAPI
Dire
ct a
cces
s
Dire
ct a
cces
s
Networkdrivers
Storagedrivers
feature section: virtualization in the mainstream
DELL POWER SOLUTIONS | August 200736
feature section: virtualization in the mainstream
DELL POWER SOLUTIONS | August 200738 Reprinted from Dell Power Solutions, August 2007. Copyright © 2007 Dell Inc. All rights reserved.
of memory, PCI Express I/O, Serial Attached SCSI (SAS), 4 Gbps Fibre
Channel storage, and efficient power consumption. Administrators can
manage Dell systems running XenEnterprise using Dell OpenManage
Server Administrator (OMSA) and Dell OpenManage IT Assistant.
installing Dell openmanage server administrator on Xenenterprise 3.2 hosts OSMA is a comprehensive systems management tool for Dell PowerEdge
servers designed to simplify administration of local and remote systems
through a set of integrated services. It resides solely on managed sys-
tems and is accessible both locally and remotely; on XenEnterprise
virtualized systems, the OMSA agent resides in Dom0. Although OMSA
is not supported by Dell inside CentOS distributions, administrators
can use it to manage XenEnterprise hosts by performing the following
steps, which apply to OMSA 5.2 on a server running Red Hat® Enterprise
Linux 4:
1. Download the Dell OpenManage Server Administrator Managed
Node software package for Red Hat Enterprise Linux 4 from
support.dell.com.
2. Copy the tar.gz file to the XenEnterprise host.
3. Extract the tar.gz file with the command tar -zxvf filename
.tar.gz.
4. Edit the setup script to enable installation on a XenEnterprise host.
To do this, first change the permissions of the setup.sh script by
using the command chmod +w setup.sh. Next, edit the file with
the vi setup.sh command and locate the following at line 2,976:
# Set default values for return variables.
GBL_OS_TYPE=${GBL_OS_TYPE_UKNOWN}
GBL_OS_TYPE_STRING="UKNOWN"
Change these lines to the following, then save the changes and
close the file:
# Set default values for return variables.
GBL_OS_TYPE=${GBL_OS_TYPE_RHEL4}
GBL_OS_TYPE_STRING="RHEL4”
5. Install the compat-libstdc++-33-3.2.3-47.3.i386.rpm package on
the XenEnterprise host by using the following command from the
linux/RPMS/supportRPMS directory:
rpm –ivh compat-libstdc++-33-3.2.3-47.3.i386.rpm
6. Download the procmail-3.22-14.i386.rpm package from
mirror.centos.org/centos/4/os/i386/CentOS/RPMS, then install
it with the following command:
rpm –ivh procmail-3.22-14.i386.rpm
7. Start the OMSA installation using the command ./setup.sh, then
follow the on-screen instructions to complete the installation.
8. After completing the installation, change the firewall settings to
allow communication through the ports that OMSA uses. First, edit
the firewall rules with the vi /etc/sysconfig/iptables com-
mand. Next, add the following rules to the INPUT section below the
:INPUT ACCEPT [0:0] line to open the OMSA and Simple
Network Management Protocol (SNMP) ports, then save and close
the file:
-A INPUT -p tcp -m tcp --sport 1024:65535
–-dport 1311 -m state --state NEW -j ACCEPT
-A INPUT -p tcp -m tcp --sport 1024:65535
--dport 1311 -j ACCEPT
-A INPUT -p udp --dport 161 -j ACCEPT
Finally, restart the iptables service with the command service
iptables restart.
9. Open the server’s OMSA Web interface at https://server:1311 and
log in with the root username and password.
Note: Because OMSA is not supported by Dell inside CentOS distribu-
tions, the preceding steps are provided without implied support or
warranty.
configuring Dell openmanage it assistant to manage Xenenterprise hosts Dell OpenManage IT Assistant is a comprehensive, standards-based con-
sole for managing Dell servers, storage, tape libraries, network switches, Figure 3. One-to-many administrator GUI for the XenSource XenServer family
39www.dell.com/powersolutionsReprinted from Dell Power Solutions, August 2007. Copyright © 2007 Dell Inc. All rights reserved.
printers, and client systems. It allows administrators to use a central
Web browser–based console to monitor the health and status of Dell
systems, capture events and alerts generated by Dell servers running
OMSA, configure actions based on these events and alerts, and monitor
server performance statistics such as processor and memory utilization,
I/O, and so on.
Dell OpenManage IT Assistant uses SNMP to manage Dell servers
running Linux distributions. If administrators have installed the IT Assistant
management application on their network, they can use IT Assistant to
manage XenEnterprise hosts. To do so, they should edit the /etc/snmp/
snmpd.conf file on the XenServer hosts as follows:
1. Locate the line that reads com2sec notConfigUser default
public, then replace public with the new SNMP community
name.
2. Add the following line at the end of the file (where ipaddress is
the IP address of the IT Assistant server and community is the
SNMP community name):
trapsink ipaddress community
3. Save the snmpd.conf file and restart the snmpd service with the
command service snmpd restart.
For more information on IT Assistant, see the Dell OpenManage IT
Assistant User’s Guide.
Supporting XenSource environments XenSource provides freely available support resources at www.xensource
.com/support, including software documentation, a searchable knowl-
edge base, and discussion forums. XenSource also offers paid support
services that allow administrators to enter support cases and upload
related information such as logs and screenshots through a Web-based
interface. Additional details on these paid support services are available
in the XenSource Technical Support Guide at www.xensource.com/
support/guide/tech_support_guide.html.
Implementing scalable, efficient virtualization The XenSource XenEnterprise paravirtualization architecture can provide
several advantages over emulation virtualization, including near-native
VM performance and the efficient allocation of physical resources. As a
virtualization platform running on Dell PowerEdge servers and managed
by Dell OpenManage software, XenEnterprise can play a key role in build-
ing a scalable, efficient enterprise data center.
Victor Mashayekhi, Ph.D., is the engineering manager for the Dell
Scalable Systems Group, and is responsible for product development for
high-performance computing clusters, remote computing, unified
communication, virtualization, custom solutions, and Dell solutions advi-
sors. Victor has a B.A., M.S., and Ph.D. in Computer Science from the
University of Minnesota.
Puneet Dhawan is a systems engineer in the Dell Virtualization Solutions
Engineering Group, where he currently develops scalable and responsive
enterprise computing solutions. Puneet has a bachelor’s degree in
Electrical Engineering from Punjab Engineering College (PEC) and a mas-
ter’s degree in Computer Engineering from Texas A&M University.
Simon Crosby is the chief technology officer at XenSource. Previously, he
was a principal engineer at Intel; founder and chief technology officer of
CPlane Inc., a network optimization software vendor; and tenured faculty
member at the University of Cambridge, where he led research on network
performance and multimedia operating systems. He is the author of over
35 research papers and patents.
Roger B. A. Klorese is the senior director of product and solutions market-
ing at XenSource. He previously served as vice president of marketing at
Trigence and Sychron, and in a variety of marketing, product management,
and product support roles at VMware, Veritas, Hewlett-Packard, Consera,
Sendmail, MIPS Computer Systems, Celerity Computing, and Prime
Computer. He studied Critical Studies (English and Film) and Computer
Science at Dartmouth College.
QUICK LINKS
XenSource: www.xensource.com
Dell virtualization solutions: www.dell.com/virtualization
Dell OpenManage IT Assistant User’s Guide: support.dell.com/support/edocs/software/smitasst
“Xenenterprise can play a key role in building a scalable, efficient enterprise data center.”